EARTH

[1801-09-06] Stabilization/Solidification treatment of Cadmium-bearing-residue with Magnesium Slag

○Yujie Chen¹, Shun Zhu¹, Yanjie Liang^1,2, Bing Peng^1,2, Hui Liu^1,2 (1. Central South University, 2. Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution)

Chairman：Mayumi Ito（Hokkaido University)

Keywords:Stabilization/solidification, Magnesium Slag, Cadmium, TCLP, calcium silicate

The present study investigates the stabilization process of simulated cadmium-bearing-residue by using magnesium slag since the high hydration and gelling properties. The results of toxicity characteristic leaching procedure (TCLP) showed that the leaching concentration of Cd decreased from 1415. mg/L to less than 1 mg/L with adding 4 wt% of magnesium slag. The sequential extraction experiment, BCR(European Community Bureau of Reference), confirmed that Cd phase variation during the procedure, and it revealed that magnesium slag can promote the conversion of cadmium from acid extractable form to reducible and oxidizable form. This result can be supported by XRD analysis, which indicated that the Ca(II) could be replaced by Cd(II) silicate due to the common valence state and a similar ionic radius of Cd and Ca. The results of SEM micrographs and EDX had demonstrated that Cd was mainly stabilized in the structure of calcium silicate.